Regenerative telegraph repeater, one or more code combinations per start-stop cycle



Oct, 11, 194$. w, BACQN REGENERATIVE TELEGRAPH REPEATER, ONE OR MORE CODE COMBINATIONS PER START-STOP CYCLE Filed Oct. 24, 1945 2 She ts-Sheet l lA/VENTOR W M BACON BY gauze ATTORNEY W. M. BACON REGENERATIVE TELEGRAPH REPEATER,

Oct. 13, 1 .949.

ONE OR MORE CODE COMBINATIONS PER START-STOP CYCLE 2 Sheets-Sheet 2 Filed 001;. 2 4

INVENTOR W M. BACON avjvw a c Q QN & .4 4

I854 R50 Q Evin lilEHl' m at ATTORNEY Patented Oct. 11, 1949 REGENERATIVE TELEGRAPH REPEATER, ONE OR MORE CODE COMBINATIONS PER START-STU? CYCLE Walter M. Bacon,

to Bell Telephone New York, N. Y., assignor to Laboratories, Incorporated,

New York, N. 57., a corporation of New York Application October 24, 1945, Serial No. 624,291

9 Claims. 1

This invention relates to regenerative repeaters for multiplex telegraph systems. More particularly, this invention is a regenerative repeater for use in a start-stop multielement permutation code telegraph system wherein the usual signal elements of the multielement permutation code signaling system have been shortened so that during an interval corresponding to the duration of a single element of normal length, two signal elements are transmitted for two difierent channels. Such systems have been found useful, particularly when weather conditions permit, for application on long radio channels to increase the capacity of such facilities. They are employed also on the connected land lines and the problem of regeneration arises, particularly when the double-channel single start-stop arrangement is extended over land lines. When the weather conditions are adverse, it is necessary to revert to single-channel transmission. Since the cooperating receiving teletypewriters are adjusted to respond to signal elements displaced from their normal position, the reversion to single-channel operation requires that the signals for single-channel operation be adapted to the adjustment of the teletypewriter in the particular single channel which is to continue in operation if the delay involved in the readjustment in the teletypewriter to normal conditions is to be avoided. This complicates the problem of regeneration.

In such multiplex systems as presently arranged, a Single start pulse, which serves for both channels, is followed by the first signal element of the multielement permutation code combination for the first channel and then the first signal element for the second channel. Thereafter the second signal element for the first channel is transmitted followed by the second signal element for the second channel and so on until, in the case .of a five-element permutation code, five signal elements, each equal in length to one-half the duration of a single normal character-forming signal element have been transmitted for each channel. Thereafter a single stop pulse will be transmitted to serve both channels. The total duration of the whole cycle is the same as the duration of a start-stop cycle for a single multielement permutation code combination having character-forming signal elements of normal duration. Systems operating as described in the foregoing are disclosed in E. F. Watson Patent 2,231,375, granted February '11, 1941 and in E. F. Watson Patent No. 2,416,723, March 4,1947. .In the improved system of. Patent No. 2,416,723, a

single telegraph transmitting unit is arranged in such manner that it can be operated to transmit either signal elements of normal length for a single channel or signal elements of half normal length for two channels by the operation of a single switch associated with the improved telegraph transmitting apparatus. The arrangement of the present invention will cooperate with the arrangements of the above-mentioned patent and application.

It is necessary to make adjustments in the receiving apparatus which may for instance be a teletypewriter receiver such as disclosed in Patent 1,904,164 Morton et al., April 18, 1933, to function with the two-channel system. This is done by properly orienting the receiving cams on the cooperating receiving units so that they will respond to the respective permutation code signal elements intended for each. The present invention provides a regenerative repeater arranged to cooperate with such systems.

It is an object of the present invention to provide an improved regenerative telegraph repeater for use with single start-stop multiplex telegraph systems. It is a further object of the present invention to provide a regenerative repeater to function with single start-stop multiplex permutation code signal systems in which the duration of the normal multielement permutation code character-forming signal elements has been shortened so that a signal element for each of two different channels is transmitted during the interval normally allocated for the transmission of a single signal element for a single channel.

It is a further object of the present invention to provide a regenerative repeater for a single start-stop multiplex system arranged to impress the regenerative signals either on a single channel or on a separate channel for each of the component multielement permutation groups in the multiplex system.

The foregoing objects as well as the features of the present invention may be more readily understood from the following description when read with reference to the attached drawings in which Fig. 1 shows an exemplary transmission system incorporating a typical embodiment of the arrangement wherein the two combinations of signals regenerated in each cycle of operation of the regenerator are impressed on a single outgoing channel and Fig. 2 is an exemplary transmission system incorporating a typical embodiment of the invention wherein each of the two combinations of signals regenerated in each cycle of operation of the regenerator is impressed on an 3 individual one of two separate outgoing channels directly.

Refer now to Fig. 1. Before proceeding with the detailed description of operation of the system per Fig. 1, its operation will be described in general.

It will be assumed that .conductors IOI and I02 are incoming either from the output of a radio receiver, telegraph transmitter, or from a distant. telegraph repeater station. The incoming signals are impressed on the line receiving-relay I00. The line receiving relay I 03 in turn impresses the signals on the regenerative repeater receivingrelay I04. The regenerative repeaterfreceiving relay Hid impresses the signals through the transmittingdistributor I05 and on the delay circuit comprising relays I06 and I01 and the circuit of conclen;-

ser I 40. This circuit introduces a delay equal to one-half of the duration of one of the signal elements comprising one of the two characterformingcombinations of a cycle, before the start signal is impressed on relay I08. Regenerative repeater sending relay I08impresses the regenerated signals on the line sending relay I 09 which retransmits them to the outgoing channel formed by conductors [I and III. Relays I and I01 are involved only in the transmission of the start signal and their primary function is to delay the beginning of the start signal and then to pass it onto sending relay I08 which transmits-it to the outgoing line IIO, III through rela I00.

The system per Fig. 1, as hereinbeiore mentioned, isintended to impress regenerative signals for two separate multi-element permutation codes on the single outgoing line formed by condctors H0 and I I I.

The start signal element impressed on distributor I05starts arm I18 in rotation. After the start signal'has been transmitted, the control of relay I08 is assumed by distributor I 05 directly, without the intervention of the delay circuit. The elements of thetwo multielement code combinations are transmitted alternately as the arm' I18 continues to rotate. The transmission of each signal element is displaced so that its proper nature-may be determinedby sensing the middle portion of the incoming signal. This is cared for automatically by the introduction of the delay before the start signal is transmitted, after which a normal full lengthstart signal is transmitted.

When arm I18 has rotated to a position such that brush I80 engages segment I10, a marking signal is transmitted as a stop signal from positive battery I88 which is permanently connected to segment I90 to relay I08.

It was also mentioned above that at times it is desirable to arrange the system so that instead of transmitting two permutation groups, each having signals of one-half the normal length, single permutation code groups of signals of normal length are transmitted. In order to arrange the system for such operation, key I91 is provided.

When this key is in the normal position indicated in Fig. 1, the systemis arranged to transmit the signal elements of two permutation code combina tions alternately. When the key I91 is operated to its lower position, the system per Fig. 1 is arranged to transmit a single permutation code combination having signal elements of the usual normal length.

The detailed operation of Fig. 1 will now be described. First, the condition of the various units of the system per Fig. 1, while it is in the normal idle condition awaiting the receptionof signals, will be described.

The path extending through conductor I0 I, the

' top winding of relay I03 and conductor I02 is closed by means not shown so that current flows through the top winding of relay I 03. The effect of this current is tending to actuate the armature of relay I03 to engage with its right-hand or marking contact. A circuit may be traced from positive battery II4 through resistance H5, bottom winding of relay I03 and resistance H0 to negativebatter-y H1. The effect of current flowing in'this path tends to actuate the armature of relay I03'to ward'the left to engage with its spacing contact. However, the efiect of the current flowing in the top winding when the circuit through conductors IIII and I02 is closed is dominant and the armature of relay I03 is maintained in engagement with. its right-hand or marking contact. for the idle and marking conditions. While the armature of relay I03 is in engagement with its right-hand .or marking contact, a circuit may be traced from negative battery I I1 through resistance II8, marking contact and armature of relay I03 and the top winding of relay I00 to the junction between resistances I20 and I2I which connect to grounded positive battery I22 and to grounded negative battery I23, respectively. The path through the bottom winding of relay lMextendsfrom the junction between resistances I25 and I26, which connect to grounded positive and negative battery, respectively, through resistance I56 and the top winding of relay I08 tojunction point I82; From junction point I82 one branch extends through the armature of relay I01 to the, marking contact of relay I01 whichis open. A second branch extends to junction point I92 from which point one branch extends directly. to segments IA to 5A anda second rbranch extends to junction point I94. From junction point I94 one branch extends through contact I 63 of key I I 3.to segments IE to 5B. A second branch extends to segment I10. While arm I18 is in the stop position, each of the segments: tow'hi-ch: the path through the bottom winding of relay IIl l extends is open. Therefore, the bottomwinding of relay I04 and the top winding of relay I00 are deenergized for the idle condition. The effect of current flowing in the top winding of relay I04 maintains its armature in engagement withits right-hand or marking contact. While the armature of relay I04 is in engagement with its right-hand or marking contact, a circuit may betraced from negative battery I28 through resistance I24, right-hand or marking contact and armature of relay I04, inner ring I'M of transmitting-distributor I05, brush I19 which connects internally to brush I80, and rest segment I15 to parallel branches. One branch extends through the-winding of the stop magnet H3 and resistance I 13to negative battery I12. The other branchextends through the bottom winding of timing relay I 06 and resistance I30 to negative battery I3I. Attention is called to the fact that negative battery I23, at one end of the circuit last traced, connects'to negative battery H2 in one of the parallel branches and to negative battery' I 3| in the other of the parallel branches. No current flows in this circuit under this condition. Stop magnet. II3,is deenergized. Spring I 1| maintainsthe right-hand end of lever I69 in the path of the shoulder of cam I10 so that the rotatable arm I18 of distributor I05 is at rest in the position shown. A circuit may be traced from negatve battery I3I.through resistance I32, top winding of-relay I06 andresistan-ce I33 to positive battery I34. The eifect'of the current flowresistance I43, top winding of ing in this path tends to actuate the armature of relay I05 to engage ing contact and since it is unopposed the .armature of relay I05 will be maintained in engagement with its left-hand or marking contact for this condition. When the armature of relay I05 is in engagement with its left-hand or marking contact, a circuit may be traced from positive battery I34 through resistance I35, armature and left-hand or marking contact of relay junction of a parallel circuit. One branch of the parallel circuit extends through the bottom winding of relay I01 and resistance I36 to negative battery I31. The other branch extends through condenser I40 and resistance I39 to positive battery I30. The effect of the current flowing through the bottom .winding of relay I01 tends to actuate the armature of relay I01 towards its right-hand or marking contact. A circuit may also be traced from positive battery I42 through relay I01 and, assuming that the key I01 is in the position indicated through contact I62, potentiometer I98 and resistance I50 to negative battery I58. The effect of the current flowing in this circuit tends to actuate the armature of relay I01 toward its lefthand or spacing contact. The effect of the current flowing through the bottom winding of relay I01 for this condition is dominant over the effect of the current flowing in the top winding of relay I01 and the armature of relay I01 is maintained in engagement with its right-hand or marking contact. It was shown above that no current flows through the top winding of relay I08 for the idle condition. shown locked in its right-hand or marking position. It is actuated to this position under the influence of current flowing in its top or operating winding as brushes I19 and I80 traversed stop segments I90 and of the last preceding cycle at which time negative battery I80 through resistance I89 was in series with the top winding of relay I03 to actuate the armature of relay I08 to its right-hand or marking position. The armature of relay I is locked in this position by the effect of current flowing from negative battery I52 through resistances IEI and I50, marking contact and armature of relay I08 and resistance I53 to the junction between resistances I54 and positive and negative battery, respectively. To anticipate, it is pointed out that the armature of relay I08 is locked in whatever position it as sumes by the effect of current flowing either from positive or negative battery connected to its marking and spacing contacts, respectively. This maintains the particular signaling condition last received from the distributor for an interval until the relay is actuated to the opposite position.

The effect of the current in the top winding of relay I08 when flowing and when of opposite effect to the locking current, dominates the effect of the current in the locking circuit. A circuit may be traced from negative battery I52 through resistance II, resistance I50, right-hand or marking,

contact and armature of relay I08 through the winding of relay I09 to the junction between resistances I45 and I45 which connect to grounded positive battery I44 and grounded negative battery I41,respectively. The current path for the idle or marking condition maintains the armatur of relay I09 actuated to the righthand position to engage its marking contact and maintains the path through conductors H0 and III in the outgoingline closed.

with its left-hand or mark- I06 to the 1 The armature of relay I08 is.

I16, respectively, at the end I51 which connect to grounded flowing in this tion in an interval which is slightly less than the time required for the transmission of a normal single cycle of five-element permutation code start-stop signals. The difference is compensated by arresting arm I10 during a portion of the stop signal. It is,t0 be understood, however, that the present invention is not limited to service in a five-element system. The number of elements comprising the code may be varied and the time of transmission of a start-stop cycle may be varied so long as the number of segments in the regenerator I05 and the time of a regenerating cycle con orm to the number of elements in the code as transmitted and the duration of a cycle as transmitted from the originating source minus the compensating interval.

From the foregoing the condition of the various apparatus elements of Fig. 1 for the idle or stop condition, which is a marking condition, while awaiting the reception of a two-combination single start-stop signal train should be understood. The manner in which the circuit per Fig. l responds to the reception of a signal train will now be described.

The first signal element which is received from line IOI, I02 is a no-current or starting signal element of normal length. In response to this the top winding of relay I03 will be deenergized and the armature of relay I03 will be actuated to engage with its left-hand or spacing contact. Positive battery will be connected through resistance H9 and the spacing contact of relay I03 through the path which has heretofore been traced through the top winding of relay I04. In

response to this the armature of relay I04 will be actuated to engage with its left-had or. spacing contact. Positive battery I21 will be connected through resistance I29 and the spacing contact of relay I04 through the path which has heretofore been traced through the armature. of stop magnet I I3 and the bottom winding of relay I06. Stop magnet I I3 will be energized. The armature lever I69 wil1 be rotated clockwise around its fixed center against the influence of spring I1 I and its right-hand portion will disengage from the shoulder on the periphery of cam I10 permitting rotatable arm I18 to start in rotation clockwise. Simultaneously, the armature of relay I00 will be actuated to the right to engage with its spacing contact, disconnectin positive battery I34 from the circuit which has heretofore been traced through the bottom winding of relay I01. Relay I01 will not release instantly, however. When positive battery I34 is disconnected from the right-hand terminal of condenser I40, positive battery I38 will flow through resistance I39 and condenser I40 for an interval until the condenser I40 is charged. The capacity of condenser I40 and the magnitude of the other elements in this circuit are so chosen that the arms;- ture of relay I01 will be maintained in engagement with its right-hand or marking contact for an interval. At the termination of this interval the armature of relay I01 will be actuated to the left to engage with its spacing contact. This connects positive battery through resistance MI and the spacing contact and armature. of; relay I01 to the circuit which has heretofore been traced through the upper winding of relay I08 and the bottom windingof relay I04. In response to this the armature of relay ease with its left-hand or spacing contact and the armature of relay I 04 will be locked in engagement with its left-hand or spacing contact. Meanwhile, arm I18 continues to rotate. The

constants of the circuit including condenser I40 are so chosen that after the armature of relay I 01 engages with its left-hand or spacing contact, an interval of 22 milliseconds, which is equal to the duration of a normal start pulse, will elapse before arm I18 has rotated into such position that brush I 80 will begin to make contact with segment IB of distributor I05. When the armature of relay I 08 engages with its spacing contact positive battery I48 will be connected through resistance I49 and the spacing contact and armature of relay I08 and through the circuits which have been traced through the winding of relay I09 and the bottom winding of relay I 08. The armature of relay I09 will be actuated to its left-hand or spacingcontact, opening the circuit through conductors H and III, to transmit aspacing signal out over the line and the armature of relay I08 will be locked in engagement with its left-hand or spacing contact by the eifect of the current flowing through its bottom winding. While the armature of relay I04 is locked in the spacing condition-it will not respond to any signal received by relay I03 from the incoming line. When arm I18 has. rotated into such position that brush I80 disengages from rest segment I15, the circuit through the bottom winding of relay I05 will be opened. The armature of relay I 06 will bev actuated under the influence of the current in its upper winding to reengage with its left-hand or marking contact. This will reclose the circuit through: the bottom winding or relay I01 and the armature of relay I 01 will again be actuated to reengage with its right-hand or marking contact. This in turn opens the path through the top winding of relay I08 andthe bottom winding of relay I04. Relay I08 will remain locked with its armature in the spacing position since its locking circuit which is local to the relay remains closed. Relay I04, however, will be unlocked and 'can'respond to incoming signals. However, attention is called to the .fact that segment I11 which succeeds the rest segment is not connected to any external circuit and theref re any portion of a signal which may be received by ring, segment I14 from relay I04 while brush I80 is traversing, segment I11 will be ineffective.

After an interval of 22 milliseconds, which is equal to a full starting signal element, plus the delay interval introduced by the delay circuit, has elapsed, brush I80 will start to engage segment IB of distributor I85. In the meantime, the succeeding signal element of the signaltrain which is the first signal element for channel B will have been received by relay I03 and. impressed on relay I04. Relay I04will= have in turn impressed the signal element on the solid con ducting ring segment I14 of distributor I05; Brush I 80 will engage segment IB just as the middle portion of the signal element is being received and the signal element will be impressed through segment IB and a circuit which has been traced in the reverse direction through contact I63 of key I91 and the top and bottom windings of relays I08 and I04, respectively. In the event I08 will be actuated to enr that the signal element is a marking signal element, negative battery I23 will be impressed on this path, and in the event that it is a spacing signal element, positive battery I21 will be impressed on this path. In respOnSe to this the armature of relay I08 will be actuated either to its marking or spacing contact and the armature of relay I09 will be actuated to either open or close the path through conductors I I0 and II I. Arm I18 will engage each succeeding active segment IA, 2B, 2A, etc., as the middle portion of the corresponding signal element is being received. Relays I08 and I09 willfollow these sig nal elements and transmit them to line III), III.

Attention is called to the fact that all B segments are connected in parallel through contact I63 to the top winding of relay I08 and all A segments are-connected in parallel and extend directly through the top winding of relay I08. When key I91 is in the position shown, the regenerative repeater per Fig. 1 will regenerate two separate multielement permutation code combinations for each cycle of operation. Whenkey I 91 is actuated to its downvposition, contact I63 is opened. All of the B segments will be disconnected from the top winding ofrelay IIIB. All of the A segments, however, will be unaifected by the operation of the key. As a result of. this, the signals corresponding to a single combination only, namely, the A combination will be transmitted. The armature of relay I08 will then be locked in whichever position it assumes for an interval such that the total duration of a signal element is equal to the duration of a full signal element of normal length rather than to half a signal element.

The operation of key I91 to its lower position by opening contact I62 and closing contact I BI substitutes potentiometer II and resistance I59 for potentiometer I08 and resistance I59 in the circuit which extends through the top Winding of relay I81. This is necessary in order to change the current flowing through the top Winding of relay III? for the two conditions so as to insure the proper timing of the operation of relay I01.

It is emphasized that. corresponding signal elements as received from line I'0I, I02 and as retransmitted after regeneration to line II 0, III are slightly displaced in time'in relation to each other. In the arrangement per Fig. 1, the start signal received from the line is impressed on the regenerative repeater circuit, immediately upon its reception, through relay I04 and distributor I05. However, relays I06 and I01 and the circuit of condenser I40 introduce a delay interval before relay I08 is permitted to retransmit the regenerated start signal through relay I09 to the outgoing line. The interval of the delay is equal to the duration of one-quarter of a normal full length character-forming signal element of a five-element permutation code or to one-half of a shortened character-forming signal element when the system is arranged, as herein, to transmit two character-forming code combinations in the interval in which a single five-element code combination is normally transmitted.

The. position of the rotatable arm I18 is orientable. Its stop position and speed of rotation are arranged so that brush I arrives at the righthand end of segment I B at theinstant that the center of the first character forming signal element of the two code combinations is being received Durin the interval from the start of rotation of arm I 18 until brush I80 engages segment IB, an interval elapses which is equal to the interval required for the delay, which corresponds to one-half of the interval required for the reception of a single one of the five characterforming signal elements in either of the two code combinations, plus a full normal start signal element of 22 milliseconds. Brush I80 will sweep off rest segment I15 at the end of 22 milliseconds corresponding to the end of the received start signal and will be traversin inactive segment I11 during the interval while the first half of signal element IB is being received. But the beginning of transmission of the outgoing start signal by relay I09 will be delayed by the interaction of relays I06 and I01 and the circuit of condenser I40 for an interval equal to the interval required for the traversal of segment I11 by brush I80. During the interval while brush I80 is traversing segment IB, which corresponds to the interval required for the reception of the latter half of the first character-forming element of the B code combination, relay I08 will be under direct control of segment IB for the transmission of a, portion of a marking or spacing signal element. Then during an interval while the first half of signal element IA is being received by relays I03 and I04 and while brush I80 is traversing inactive segment I86, relay I08 will be locked by its own local circuit in whatever position it had assumed while under the influence of segment IB. As a result of this the duration of the character-forming signal elements transmitted to the line IIO, III will comprise two portions. The first represents an interval while the brush I80 traverses a segment such as to the interval of the latter half of the signal element received from line IOI, I02, and the second represents an interval while brush I80 traverses a succeeding inactive segment such as I86 while the first element is being received from the line IOI, I02 during which interval sending relay I08 is locked with the proper sending signal element stored therein.

The latter half of the fifth or last characteriorming signal element of combination A is transmitted by locked relay I08, while brush I80 traverses inactive segment I81. Then brush I80 sweeps onto the active stop segment I16. Positive battery I88 is permanently connected through resistance I89 to segment I90. When brushes I19 and I80 bridge segments I90 and I16, a cirsuit is extended through the top winding of relay I08. The eiTect of current in this circuit transmits a marking signal as a stop signal through lines H8, III. The length of the active stop segment I16 is short and the segment is traversed in less time than the actual duration of a stop signal. The function of active stop segment I16 is to transmit a marking signal element to relay I08 and to permit relay I08 to lock in the marking position. Then brush I80 sweeps off the active stop segments I16 and brushes I19 and I80 sweep onto large conducting ring segment I14 and rest segment I15, respectively.

Attention is called to the fact that the actual reception of the last character-forming element A of the A combination from line IOI, I02 terminates and the reception of the stop signal element from line IOI, I02 starts as brush I80 sweeps off segment 5A and engages segment I81. However, segment I81 is inactive. During the interval while the first portion of the stop signal element is actually being received from line IOI, I02, brush I80 is traversing segment IB corresponding half of the succeeding signal 4 I81 and the second half of signal element 5A which is stored in relay I08 is being transmitted. The time of traverse by brush I of active stop signal segment I16 as mentioned above, is actually considerably shorter than a normal stop signal element. The brush I80 sweeps ofi active stop segment I16 and onto rest segment I16 where it arrives at the stop position shortly before the end of reception from line IOI, I02 of a stop interval of normal length.

The period of rotation of arm I18 is slightly less in duration than the period of transmission of one cycle. of standard five-element start-stop permutation code telegraph signals. The duration of a cycle of the shortened element double code combination including the start-stop signal elements is the same as the duration of the normal five-element permutation code start-stop cycle. Brush I88traverses segments I81, I16 and the portion of segment I15 up to the stop position, where arm I18 is arrested by the released lever I69, during an interval slightly less than the duration of a normal stop signal and arm I18 and brush I88 are arrested in the stop position during the remainder of the interval while the normal stop signal is actually being received from line IIII, I82. But only during a portion of this normal stop signal interval, namely, While brush I80 engages segment I16, after thesecond half of signal element SA has been transmitted, while brush I38 was traversing segment I8'I, will the distributor I05 actually be transmitting a stop signal to relay I08. During the interval while brush I88 traverses the portion of segment I16 up to the stop position and during the interval while brush I88 is arrested, the stop signal will be locked in relay I08. The arm I18 makes one revolution and then is stopped. The transmission of the last portion of the normal stop signal from relay I08 will occur after the rotation of arm I18 stops while relay I08 remains locked. In other words, at the instant when the stop arm I18 reaches the stop position, a stop signal of normal length will not have been transmitted. The transmission of the stop signal is completed during the interval while the stop arm remains at rest.

Refer now to Fig. 2. In the arrangement per Fig. 2 the operation is essentially the same as in Fig. 1 except that separate outgoing channels are provided for the'two combinations. Relays 206A, 201A, 208A and 209A are assigned to channel A and relays 2863, 201328813 and 209B are assigned to channel B the relays in each channel correspond in their function and in their detailed operation to relays I86, I01, I08 and I89 in Fig. 1. Channel A is controlled by the A segments on transmitter-distributor 205 and channel B is controlled by the B segment on the distributor. In the arrangement per Fig. 2 no key corresponding to key I91 is provided since none is required when separate outgoingchannels are employed as in Fig. 2.

In Fig. 2, the operating windings of relays 206A and 206B which correspond to relay I06 in Fig. 1 are connectedin series and separate stop segments have been provided on the distributor for both the A and B channels which control the respective relays 208A and 2083 for the particular channel. The actual reception of a stop signal from line 20 I 202 starts when brush 280 sweeps off segment 5A of distributor 205. The actual transmission of the stop signal for channel B does not start until brush 280 engages stop segment B. The

actual transmission of the stop signal for channel A will not start untilbrush 280 engages stop segment A. Arm 218 is arrested at the stop position and the stop interval for each channel persists after the brush stop. The stop interval for channel A will include an interval determined by the circuit of condenser 240B when continuous signals are coming in. During these intervals the armatures of relays 2073 and 281A for the respective channels will be maintained in their respective marking positions as shown in Fig. 2. After these respective intervals elapse the armatures of relays 201MB and 201A will be actuated to their respective spacing positions to permit the actual transmission of the start signals through relays M383 and 208A and relays 209B and 209A to the B and A channels at the respective proper instants. Thereafter, spacing signals of durations equal to full length start signals of 22 milliseconds will be transmitted over the B and A channels while brush 280 is traveling to the IB and IA segments, respectively.

What is claimed is:

1. In a telegraph system, an incoming telegraph circuit, an outgoing telegraph circuit, a regenerative repeater intermediate said. circuits, means in said incoming circuit for receiving at a first time a train of telegraph signal elements consisting of a start signal element of normal duration followed by two complete individual code combinations of multielement permutation code character forming or functional signal elements and a stop signal element of normal duration, each of said character forming or functional signal elements in each of said two combinations being one-half normal duration and arranged alternately, each signal element of one combina tion followed consecutively by a correspondingly numbered. signal element of the other combination, means for impressing'all of said signals on said regenerative repeater, means in said repeater for regenerating said signals, means in said repeater for impressing said regenerated signals on said outgoing circuit, means in said circuit for receiving at a second time a single start-stop multielement permutation code signal combination, means for regenerating said single combination and means for impressing said single regenerated combination on said outgoing circuit, said regenerating means for said trainof elements and for said single combination comprising a single transmitting device of substantially constant speed of operation per cycle-and arranged to regenerate said train of elements and said single combination in equal intervals.

2. In a telegraph system,a regenerative telegraph repeater, means in said repeater for receiving at a first time a train of telegraph signal elements consisting of a single start signal element, a single stop signal element, each of said elements of normal duration and a plurality of complete character forming multielement permutation code signal combinations during the interval normally allotted for single start stop multielement permutation code signal combination having the same number of elements, means in said repeater for arranging signal elementsin correspondingly numbered positions in each of said plurality of combinations in an ordered sequence, means in said repeater for regenerating said train of signals, means in said repeater for receiving at a second time a single start-stop multielement permutation code signal combination, and means for regenerating said single combination, said regenerating means 7 elements and said for-said train of elements and for said single com--' bination comprising a single transmitting device of substantially constant speedof operation per cycle and arranged to regenerate said train of combination and a stop signal element, means in' said regenerator for regenerating said train in a time interval 7. equal to ('t1+t2'+ts), wherein i1 is the duration of said start signal element, t2 is the total duration of all of said elements in said multielement combination combined and its is the duration of said stop signal element, means sequence of a start signal element, multielement permutation code signal combinations and a stop signal element, means in said regenerator for regenerating said second train in said same time interval t equal to said same (t1+t2+ts) wherein said 251 is the duration of the start signal element of said second train, said i2 is the total duration of all of said elements of said plurality of multielement combinations in said second train combined and said is is the duration of said stop signal element of said second train.

4. A system in accordance with claim 3 in which said plurality of multielement combinations are two combinations and in which each pair of the signal elements in correspondingly numbered positions in said two combinations is arranged in numerical sequence in said second train, and means in said regenerator for regenerating each of said pairs .of elements in said second train in the time of regeneration of a single element'of acombination of said first train.

5. A system in accordance with claim 3 and means in said regenerator for delaying the regenerationof the first signal element of the first of said plurality of multielement combinations for an interval so as to-insure the detection of its proper nature.

6. A'system in accordance with claim 3 and means in said regenerator for delaying the regeneration of all of the signal elements of all of said plurality of multielement combinations for an interval so as to insure the detection of its proper nature.

7. A system in accordance with claim 3, a rotary transmitting distributor in said regenerative repeater, means on said distributor for delaying the regeneration of the first character-forming signal element of the first combination of said plurality of combinations for an interval until the nature of said element may be accurately determined, a relay circuit in said repeater, a delay circuit connected to said relay circuit for delaycircuit, responsive to said delay circuit, for preventing the operating of said transmitter until after the delay interval introduced by said distributor has elapsed.

8. In a multichannel start-stop multiplex tel graph system in which the pulses of the respecare intermingled with each other, a regenerative repeater comprising a single ring of distributor segments. areceiving relay, a transsingle combination in equal mitting relay, circuit connections between said relays and said distributor for locking said receiving relay during the time said sending relay is positioned under control of said receiving relay and a retarded delay operated under control of said receiving relay for initiating the transmission of a regenerated start pulse.

9. In a regenerative repeater, a transmittin distributor, a rotable contact on said distributor, a start segment on said distributor, a "segment on said distributor corresponding to the latter haIf of the first element or" a character-forming multielement permutation code combination, an inactive segment on said distributor separating said segments, a delay relay circuit in said repeater, a relay transmitting circuit connected :to said distributor in said repeater, a circuit interconnecting said delay circuit and said transmitting circuit, means in said repeater responsive to the reception of a start signal impulse by said repeater for activating said delay circuit, and means responsive to said activation for delaying the retransmission of said start signal impulse by said transmitting circuit for an interval equal to the time of traverse of said inactive segment by said contact.

WALTER M. BACON.

REFERENCES CITED UNITED STATES PATENTS Name Date Powell July 26, 1938 Number 

